(a) Purpose. The purpose of the airport height hazard district (AHH) is to provide regulations that provide a higher level of control from activities, situations and obstructions that could have the potential for endangering the lives and property of users of the county airport, and property or occupants of land in its vicinity. Further, the creation or establishment of an obstruction may effect existing and future instrument approach minimums of the county airport, and that obstruction may present a hazard to air navigation and/or reduce the size of areas available for the safe landing, takeoff and maneuvering of aircraft.
(b) Intent. It is the intent of this section to prevent the creation or establishment of hazards to air navigation, eliminate, remove, alter or mitigate hazards to air navigation, by regulating the height of structures, and the use of property in the vicinity of the airport.
(c) Definitions. The following words, terms and phrases, when used in this section, shall have the meanings ascribed to them in this subsection, except where the context clearly indicates a different meaning:
Airport elevation means the topographical elevation above mean sea level. At the county airport this elevation is 165 feet.
Approach surface means a surface longitudinally centered on the extended runway centerline, extending outward and upward from the end of the primary surface and at the same slope as the approach zone height limitation slope set forth in subsection (e) of this section. In plan, the perimeter of the approach surface coincides with the perimeter of the approach zone.
Conical surface means a surface extending outward and upward from the periphery of the horizontal surface at a slope of 20 to one for a horizontal distance of 4,000 feet.
Hazard to air navigation means an obstruction determined to have a substantial adverse effect on the safe and efficient utilization of the navigable air space.
Height means the height limits set forth in this section and as shown on the height hazard map, the datum shall mean sea level elevation except as otherwise specified.
Horizontal surface means the horizontal 150 feet above the established airport elevation, the perimeter of which in plan coincides with the perimeter of the horizontal zone.
Larger than utility runway means the runway that is constructed for and intended to be used for propeller driven aircraft or greater then 12,500 pounds maximum gross weight or jet powered aircraft.
Nonprecision instrument runway means the runway having an existing instrument approach procedure utilizing air navigation facilities with only horizontal guidance, or area type navigation equipment, for which a straight-in nonprecision instrument approach procedure has been approved or planned.
Obstruction means any building, structure, growth, or other object, including a mobile object which exceeds a limiting height as set out in subsection (e) of this section.
Precision instrument runway means a runway having an existing instrument approach procedure utilizing an instrument landing system (ILS) or a precision approach radar (PAR), or a runway for which a precision approach system is planned and is so indicated on the approved airport layout plan or any other planning document.
Primary surface means a surface longitudinally centered on a runway. When the runway has a specially prepared hard surface, the primary surface extends 200 feet beyond each end of that runway. For military runways, or when the runway has no specially prepared hard surface, or planned hard surface, the primary surface ends at each end of that runway. The elevation of any point on the primary surface is the same as the elevation of the nearest point on the runway centerline.
Runway means a defined area on an airport prepared for landing and takeoff of aircraft along its length.
Transitional surfaces means a surface extending outward at 90 degree angles to the runway centerline extended at a slope of seven feet horizontally for each foot vertically from the sides of the primary and approach surfaces to where they intersect the horizontal and conical approach surfaces. Transitional surfaces for those portions of the precision approach surfaces, which project through and beyond the limits of the conical surface, extend a distance of 5,000 feet measured horizontally from the edge of the approach surface and at a 90 degree angle to the extended runway centerline.
Utility runaway means a runway intended solely for the operation of aircraft using visual approach procedures.
Visual runway means a runway intended solely for the operation of aircraft using visual approach procedures.
(d) Airport hazard district zones. In order to carry out the provisions of this section, there are created and established certain zones which include all of the land lying beneath the approach surfaces, transitional surfaces, horizontal surfaces, and conical surfaces as they apply to the county airport. Such zones are identified on the airport hazard district map which is on file in the office of the county planning office and the geographical informational services office. An area located in one or more than one of the following zones is considered to be the only area in the zone with the more restrictive height regulations.
(1) Runway larger than utility visual approach zone. This zone is defined as the inner edge of the approach zone that coincides with the width of the primary surface and is 500 feet wide. The approach zone expands outward uniformly to a width of 1,500 feet at a horizontal distance of 5,000 feet from the primary surface. Its centerline is the continuation of the centerline of the runway.
(2) Runway larger than utility with a minimum greater than three-quarter mile nonprecision instrument approach zone. This zone is defined as the inner edge of this approach zone that coincides with the width of the primary surface and is 500 feet wide. The approach zone expands outward uniformly to a width of 3,500 feet at a horizontal distance of 10,000 feet from the primary surface. Its centerline is the continuation of the centerline of the runway.
(3) Runway larger than utility with a visibility minimum as low as three-quarter mile nonprecision instrument approach zone. This zone is defined as the inner edge of this approach zone that coincides with the width of the primary surface and is 1,000 feet wide. The approach zone expands outward uniformly to a width of 4,000 feet at a horizontal distance of 10,000 feet from the primary surface. Its centerline is the continuation of the centerline of the runway.
(4) Precision instrument runway approach zone. This zone is defined as the inner edge of this approach zone that coincides with the width of the primary surface and is 1,000 feet wide. The approach zone expands outward uniformly to a width of 16,000 feet at a horizontal distance of 50,000 feet from the primary surface. Its centerline is the continuation of the centerline of the runway.
(5) Transitional zone. The transitional zones are those zones that are the areas beneath the transitional surfaces.
(6) Horizontal zone. This zone is defined as that area established by swinging arcs of 5,000 feet radii for all runways designated as utility or visual and 10,000 feet for all others from the center of each and the primary surface of each runway connecting the adjacent arcs by drawing lines tangent to those arcs. The horizontal zone does not include approach and transitional at the periphery of the horizontal zone, and extends outward from a horizontal distance of 4,000 feet.
(e) Airport environs height regulations. Except as otherwise provided in this section, no building or structure shall be erected, altered, or maintained, and no tree shall be allowed to grow in any airport hazard district zone to a height in excess of the applicable height established for such zone. The maximum height regulations are as follows:
(1) Runway larger than utility visual approach zone. Slopes 20 feet outward for each foot upward beginning at the end of, and at the same elevation as the primary surface and extending to a horizontal distance of 5,000 feet along the extended runway centerline.
(2) Runway larger than utility with a visibility minimum greater than three-quarter mile nonprecision instrument approach zone. Slopes 34 feet outward for each foot upward beginning at the end of, and extending to a horizontal distance of 10,000 feet along the extended runway centerline.
(3) Runway larger than utility with a visibility minimum as low as three-quarter mile nonprecision instrument approach zone. Slopes 34 feet outward for each foot upward beginning at the end of, and at the same elevation as the primary surface and extending to a horizontal distance of 10,000 feet along the extended runway centerline.
(4) Precision instrument runway approach zone. Slopes 50 feet outward for each foot upward beginning at the end of, and at the same elevation as the primary surface and extending to a horizontal distance upward of 40 feet horizontally for each foot vertically to an additional horizontal distance of 40,000 feet along the extended runway centerline.
(5) Transitional zone. Slopes seven feet outward for each foot upward beginning at the sides of, and at the same elevation as the primary surface and the approach surface, and extending to a height of 150 feet above the airport elevation (165 feet above mean sea level). In addition to the foregoing, there are established height limits sloping seven feet outward for each foot upward beginning at the sides of, and the same elevation as the approach surface, and extending to where they intersect the conical surface. Where the precision instrument runway approach zone projects beyond the conical zone, there are established height limits sloping seven feet outward for each foot upward beginning at the sides of, and the same elevation as the approach surface and extending a horizontal distance of 5,000 feet measured at 90 degree angles to the extended runway centerline.
(6) Horizontal zone. Established at 150 feet above the airport elevation or at a height of 315 feet above mean sea level.
(7) Conical zone. Slopes 20 feet outward for each foot upward beginning at the periphery of the horizontal zone, and at 150 feet above the airport elevation and extending to a height of 350 feet above the airport elevation.
(f) Airport environs height regulations exceptions. Nothing in this section shall be construed as prohibiting the construction or maintenance of any structure, or growth of any tree to a height up to 50 feet above the surface of the land.
(g) Use regulations. Notwithstanding any other provision of this section, no use may be made of land or water within any zone established by this section in such a manner as to:
(1) Create electrical interference with navigational signals or radio communication between airport and aircraft;
(2) Make it difficult for pilots to distinguish between airport lights and other lights;
(3) Result in glare in the eyes of pilots using the airport;
(4) Impair visibility in the vicinity of the airport;
(5) Create bird strike hazards; or
(6) Otherwise in any way endanger or interfere with the landing, takeoff, or maneuvering of aircraft intending to use the airport.
(h) Existing uses. The regulations prescribed in this section shall not by construed to require the removal, alteration, lowering or other change of any structure or tree not conforming to the regulations as of May 7, 1984, or otherwise interfere with the continuance of a nonconforming use. Nothing contained in this section shall require any change in the construction, alteration, or intended use of any structure, the construction or alteration of which was begun prior to May 7, 1984.
(i) Marking and lighting. Notwithstanding the provisions of this section, the owner of any existing structure that exceeds the height requirements of subsection (e) of this section, is required to permit the installation, operation, and maintenance thereon of such markers and lights as shall be deemed necessary by the county airport authority to indicate to the operators of aircraft in the vicinity of the airport the presence of such airport obstruction. Such markers and lights shall be installed, operated, and maintained at the expense of the county airport authority.
(j) Permits required. Except as specifically provided in this subsection, no material change shall be made in the use of land, no structure shall be erected or otherwise established, and no tree shall be planted in any zone hereby created unless a permit thereof shall have been applied for and granted. Each application for a permit shall indicate the purpose for which the permit is desired, with sufficient information in order to determine whether the resulting use, structure, or tree would conform to the regulations prescribed in this article.
(1) Existing uses. No permit shall be granted that would allow the establishment or creation of an obstruction, or permit a nonconforming use, structure or tree, to become a greater hazard to air navigation than it was on May 7, 1984, or than it is when the application permit is made.
(2) Nonconforming uses, abandoned or destroyed. Whenever the planning director determines that a nonconforming structure or tree has been abandoned, or more that 80 percent physically deteriorated, destroyed, or decayed, no permit shall be granted that would allow such structure or tree to exceed the height regulations of subsection (e) of this section, or otherwise deviate from the requirements of this section.
(3) Permit exemptions.
a. In the area lying within the limits of the horizontal zone and conical zone, no permit shall be required for any structure or tree less than 75 feet of vertical height above the ground, except when, because of existing terrain, land contour, or topographic feature, such structure or tree would extend above the required height limits prescribed for such zones.
b. In areas lying within the limits of the approach zones, but at a horizontal distance of not less than 4,200 feet from each end of the runway, no permit shall be required for any structure or tree less than 75 feet of vertical height above the ground, except when such structure or tree, because of existing terrain, land contour, or topographic feature, would extend above the required height limit prescribed for such zones. Nothing contained in any of the foregoing exceptions shall be construed as permitting or intending to permit any construction, or alteration, of any structure, or growth of any tree in excess of any of the required height limits established in subsection (e) of this section.
(k) Variances. Any person desiring to erect or increase the height of any building or structure not in accordance with the regulations prescribed in this section, may apply to the board of adjustment for a variance from such regulations. The application for a variance must be accompanied by a determination letter from the Federal Aviation Administration as to the effect of the variance request on the operation of air navigation facilities and the safe, efficient use of navigable air space. An application for a variance from the requirements of this section shall be referred to the airport manager for advice as to the aeronautical effects of the variance request on the operation of the airport facilities. If the airport manager does not respond to the application request within 15 days after receipt of the application, the board of adjustment may act on its own to grant or deny such application. The board of adjustment, based on findings of fact, shall grant the variance if it:
(1) Is found that a literal application of enforcement of the regulations will result in unnecessary hardship and relief granted will not be contrary to the public interest;
(2) Will not create a hazard to air navigation;
(3) Will do no injustice; and
(4) Will be in accord with the spirit and intent of this section.
(l) Obstruction marking and lighting. Any permit or variance granted may, if such action is deemed advisable to carry out the purpose of this section, and is reasonable in the circumstances, be so conditioned as to require the owner of the structure to install, operate, and maintain, at the owner's expense, such markings and lights as necessary. If deemed proper by the board of adjustment, this condition may be modified to permit the county airport authority, at its own expense, to install, operate and maintain the necessary markings and lights.
(Ord. of 7-10-2000, § 4.5.1)